Fan blade for allowing airflow with fan in failure condition

ABSTRACT

A fan and a fan blade are provided for allowing airflow through the fan blade in a fan failure condition. The fan blade includes a peripheral member defining an opening. A flexible cover member is attached to the peripheral member for covering the fan blade opening during normal operation of the fan. The flexible cover member is hingeably attached to the peripheral member for movement away from the peripheral member enabling airflow through the fan blade opening in a fan failure condition.

FIELD OF THE INVENTION

The present invention relates generally to an air moving device, suchas, a fan for data processing systems, and more particularly, relates toa fan having a fan blade for allowing air flow through the fan blade ina fan failure condition.

DESCRIPTION OF THE RELATED ART

Various cooling arrangements have been used in data processing systemsor computer systems. Often cooling arrangements use multiple coolingdevices, such as multiple fans, blowers and other air moving devices.

For example, cooling devices for a particular system may include two ormore fans located inline within an enclosure, each normally operating.To provide effective operation, failure of one of the fans should resultin continued, substantially adequate cooling for the system.

However, with multiple conventional fans arranged inline, failure of onefan typically results in a significant drop in the cooling flow ratethrough the system components. A need exists for effective mechanism toavoid such cooling problems from a fan failure when it is stacked inline with another fan or fans.

A need exists for a more efficient arrangement for cooling components ina computer system. The cooling operation should be highly reliable, andgenerally fault tolerant to a fan failure that is stacked in line withanother fan or fans, and also be cost effective.

SUMMARY OF THE INVENTION

A principal aspect of the present invention is to provide a fan having afan blade for allowing air flow through the fan blade in a fan failurecondition. Other important aspects of the present invention are toprovide such a fan and fan blade substantially without negative effectand that overcome many of the disadvantages of prior art arrangements.

In brief, a fan and a fan blade are provided for allowing airflowthrough the fan blade in a fan failure condition. The fan blade includesa peripheral member defining an opening. A flexible cover member isattached to the peripheral member for covering the fan blade openingduring normal operation of the fan. The flexible cover member ishingeably attached to the peripheral member for movement away from theperipheral member enabling airflow through the fan blade opening in afan failure condition.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention together with the above and other objects andadvantages may best be understood from the following detaileddescription of the preferred embodiments of the invention illustrated inthe drawings, wherein:

FIG. 1 is a perspective view of a portion of a fan illustrating anexemplary fan blade in accordance with the preferred embodiment; and

FIG. 2 is a perspective view illustrating the fan and exemplary fanblade of FIG. 1 in a fan failure condition allowing airflow though thestationary fan blade in accordance with the preferred embodiment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to the drawings, in FIGS. 1 and 2 there is shown a fangenerally designated by the reference character 100 including a fanblade 102 for allowing airflow through the fan blade in a fan failurecondition. The fan 100 typically includes a plurality of fan blades 102.For example, multiple blades 102 are integrally formed spaced apartaround a rotating hub 104. The fan blade 102 includes a frame 106defining a centrally disposed, elongated opening 108. The frame 106 is aunitary member defining a periphery blade portion with the centrallydisposed, elongated opening 108.

In accordance with features of the preferred embodiment, fan 100 isadapted for use together with one or more similar fans 100 locatedinline in an airflow path, for example, in a data processing system orcomputer system.

In accordance with features of the preferred embodiment, the fan blades102 are arranged such that they move air as a normal fan blade whenoperating. If the fan fails and stops, the blades 102 allow airflow topass through the blades, generally without hindering the airflow from asecond fan behind or in front of fan 100, so that cooling is notsubstantially degraded.

The fan blades 102 are formed, for example, with each of the peripheralframe members 106 being constructed integral with the hub 104. Aflexible cover member 110 then is attached to the peripheral framemember 106 that covers the void 108 defined in the fan blade 102 duringnormal operation of the fan 100 with the rotation operation of fanblades 102.

The flexible cover member 110 is formed by a piece of selected flexiblematerial 110, such as, a polyester sheet material, a flexible syntheticfilm material sold by E. I. Du Pont De Nemours and Company under thetrademark MYLAR, or other similar flexible material.

The cover member 110 is hingeably attached onto a leading edge portion112 of the frame member 106 of the fan blade 102. The leading edgeportion 112 is the leading edge portion of the peripheral frame member106 during normal rotation operation of the fan blade 102. The covermember 110 is securely attached to or fused together with the fan bladeperipheral frame member 106 at the leading edge portion 112 of the fanblade 102, for example, with an adhesive, using heat, or with a selectedone of various other known fastening techniques.

When the fan 100 is functioning properly, air pressure caused by theoperation of the fan, forces the material 110 against the peripherymember 106 of the fan blade 102, for cooling the system generally thesame as a conventional fan blade.

In the event of a failure of one fan 100, then airflow passes throughthe respective opening 108 of all fan blades 102 of the failed orstopped fan. For example, if the front fan 100 in a fan stack fails, theair pressure from the rear fan will push the material 110 forward awayfrom the frame 106 of the failed front fan blade 102 and allow moreairflow than a conventional fan blade.

If the rear fan 100 fails, the material 110 is pulled open from theoperation of the front fan, which will reduce the restriction of airflowthat a normal fan blade would create, helping cool the system betteruntil that failed fan 100 can be replaced.

This airflow path through the fan blades 102 of the failed fan 100provides more efficient cooling for the system, until the failed fan 100is replaced.

It should be understood that the illustrated fan blade 102 is providedin simplified form sufficient for understanding the present invention.The illustrated fan blade 102 is not intended to imply architectural orfunctional limitations.

It should be understood that fan blade 102 is not limited to theconfiguration as shown in FIGS. 1 and 2. The present invention can beused with various fan blade configurations. For example, it should beunderstood that fan blade 102 is not limited to the illustrated singleopening 108, multiple openings and various patterns of openings could beprovided.

Verification of operation has been performed as follows:

-   -   (1). An initial experiment was conducted that measured the        airflow, separately, of two different fans.    -   (2). Then airflow was monitored with the two fans inline. First        with the front fan running and the rear one stopped. Then with        the front fan stopped and the rear one running. The results of        these two scenarios were very similar, but lower than the fans        singly as measured and described in (1) above.    -   (3). Then openings 108 were cut in the center of the blades 102        on one of the fans and a Mylar material 110 was attached to each        blade in a fashion that the Mylar closed over the hole when this        prototype fan 100 was operating and opened when the fan was        stopped. Then measurements were taken with this fan 100 not        running in front of the other conventional fan, which was        running. Then the fans were switched so the prototype fan 100        was stopped and placed behind the operational conventional fan        and measurements were taken. These two measurement numbers were        similar. Also, these results indicated the airflow was raised        back to the level of a single fan as measured and described        in (1) above.

While the present invention has been described with reference to thedetails of the embodiments of the invention shown in the drawing, thesedetails are not intended to limit the scope of the invention as claimedin the appended claims.

1. A fan for allowing airflow in a fan failure condition comprising: afan blade including a peripheral member defining an opening; a flexiblecover member attached to said peripheral member of said fan blade forcovering said fan blade opening during normal operation of the fan; andsaid flexible cover member moving away from said peripheral member toenable airflow through said fan blade opening in a fan failurecondition.
 2. A fan as recited in claim 1 wherein said peripheral memberis constructed integral with a fan hub.
 3. A fan as recited in claim 1wherein said flexible cover member is hingeably attached onto an edgeportion of said peripheral member; said edge portion being a leadingedge portion of said peripheral member during normal rotation operationof the fan blade.
 4. A fan as recited in claim 1 wherein said flexiblecover member is adhesively attached to said fan blade peripheral member.5. A fan as recited in claim 1 wherein said flexible cover member has athickness substantially less than said fan blade peripheral member.
 6. Afan as recited in claim 1 wherein said flexible cover member is formedby a sheet material.
 7. A fan as recited in claim 1 wherein saidflexible cover member is formed by a polyester sheet material.
 8. A fanas recited in claim 1 wherein said flexible cover member is formed of aflexible synthetic film material.
 9. A fan as recited in claim 1 whereinsaid opening is a generally centrally disposed, elongated opening in thefan blade.
 10. A fan blade for allowing airflow in a fan failurecondition comprising: a peripheral member defining an opening; aflexible cover member attached to said peripheral member for coveringsaid fan blade opening during normal rotation operation of the fanblade; and said flexible cover member moving away from the peripheralmember allowing airflow through said fan blade opening when the fanblade is stationary during a fan failure condition.
 11. A fan blade asrecited in claim 10 wherein flexible cover member is formed by aflexible synthetic film material.
 12. A fan blade as recited in claim 10wherein said peripheral member is constructed integral with a fan hub.13. A fan blade as recited in claim 10 wherein said flexible covermember is adhesively attached to said peripheral member.
 14. A fan bladeas recited in claim 10 wherein said flexible cover member is attached toan edge portion of said peripheral member; said edge portion being aleading edge portion of said peripheral member during normal rotationoperation of the fan blade.
 15. A fan blade as recited in claim 10wherein said opening is a generally centrally disposed, elongatedopening.
 16. A fan blade as recited in claim 10 wherein said flexiblecover member is formed by a polyester sheet material.